Characterization of polypropylene pipes during accelerated aging in air and water

Abstract Commercial polypropylene pipes for water transport were aged in air at 135 °C and in water at 95 °C for up to 3000 and 4000 h respectively. The protection effect of the antioxidant in the polymer was investigated by measuring the oxidation induction time (OIT) and by determining the chemical changes in the aged polymer by infrared spectrometry (FT-IR). A slight increase of crystallinity, melting temperature, crystallite dimensions with aging was observed via FT-IR, small angle light scattering (SALS) and differential scanning calorimetry (DSC). Tensile tests of two different pipes showed dramatic decay of mechanical properties with the conditioning time in air for the product less protected from thermal oxidation